Return None in json if there's no speaker. Fixes #21.
Return None in json if there's no speaker. Fixes #21.

hasgeek/funnel,jace/failconfunnel,hasgeek/funnel,piyushroshan/fossmeet,hasgeek/funnel,piyushroshan/fossmeet,piyushroshan/fossmeet,jace/failconfunnel,hasgeek/funnel,jace/failconfunnel,hasgeek/funnel